Figure 5.

DC take up and present IgG-complexed OVA to OVA-specific CD4⁺ T cells. Wild-type mice were injected i.v. with 5 µg OVA complexed to anti-OVA IgG or were left untreated (a) One hr after injection, spleen cells were isolated and sorted for DC (CD11c⁺ cells), macrophages and B cells. These cells were subsequently added to DO11·10 cells in a ratio of 2 : 1 (see Materials and methods), to analyse their ability to stimulate T cells. Proliferation of the DO11·10 cells was determined by [³H]-thymidine incorporation. (b) The same experiment as described above was performed with S : R ratios of 3 : 1 and 4 : 1. (c) To control whether the different isolated APC fractions are able to stimulate T cells, the APC were incubated with 0·01 µg/ml, 0·1 µg/ml or 1 µg/ml OVA peptide (see Materials and methods). Proliferation of the DO11.10 cells was determined as described in (a). Error bars indicate SEM of triplicate wells. One representative experiment out of four performed is presented. (d) Macrophages (pMF; 50 000; 25 000 and 12 500 cells/well) isolated from the peritoneal cavity were incubated with 1 µg OVA-IC and subsequently used for stimulation of 50 000 DO11.10-hybridoma cells. Only pMF loaded with OVA-peptide were able to activate DO11.10 cells. In contrast, DC were able to activate DO11.10 cells efficiently after incubation with IC. Activation of DO11.10 cells was detected by the production of IL-2 in the supernatant using enzyme-linked immunosorbent assay. The OD at 450 nm is depicted. Error bars indicate SEM of triplicate wells. One representative experiment out of two performed is presented.